One 12v car battery powers 2 loads. One load is 3.5A and the other is 100mA. The 100mA load is always on and when the 3.5A load gets switched on, scope readings show the amp draw momentarily dropping to half or less and voltage dropping from 12v to about 9.5v on the 100mA load. How can I maintain steady, smooth voltage and current to the low amp load during the brief time that the much larger load is energized? Would I need to use a large inductor or large cap to help momentarily sustain the 100mA current and voltage during this time?